Background: Traffic accidents are one of the most important factors contributing to the deaths and injuries of humans around the world. One of the factors causing traffic accidents is hotspots, which increase the possibility of crashes occurring due to the kind of path geometry. One of the ways of preventing crashes and increasing drivers' caution is to utilize technologies such as a hotspot warning system.Objectives: In this study, the impact of this system on narrowing the road was examined on the drivers' behavior in both clear and Foggy Weather.Methods: This experimental study was performed on a simulator with 40 drivers, including men and women. The warning system is an audio and visual kind, so a hotspot was shown in the path of the map on the system screen, and the driver received an alarm. The range in this scenario includes prewarning, from a warning to the onset of a hotspot, a hotspot zone, and after-warning. Data were analyzed using SPSS software version 20, and the significant level of tests was considered 0.05.Results: The results indicated that a hotspot warning system could affect the drivers' performance, and this effect was observed in variables including speed, steering angle, deceleration, and gas pedal performance. Moreover, the driver's behavior was significant in both clear and Foggy Weather.Conclusion: These findings can be used to correct the warning locations and times in the hotspot warning systems when approaching a narrow road.